Matt Topham, 31, who won £45 million, was approaching a left hand bend on a country road in North Cockerington, near Louth, when he turned round to look for the teddy in the footwell of his BMW X6 and veered into the opposite carriageway.
Topham said the child was upset because of his teddy but rather than stopping his vehicle to find the bear he instinctively reacted to the “piercing scream” from his son and took his eyes from the road.
As he went into the bend, Topham’s car struck an oncoming Ford Fiesta head-on, Lincoln Crown Court heard.
Mary Jane Regler, 75, who was a front seat passenger in the Fiesta, was killed as a result. Her husband Rodney, who was driving, was seriously injured.
The couple were returning home after visiting their son for a family Christmas Day dinner.
Topham and his wife were in separate vehicles, and heading for home at around 5.30pm after visiting his wife’s parents at their home at Rushmoor Country Park, when the collision occurred, the jury was told.
Mr Regler, 77, survived but suffered serious injuries including fractures to his right heel and ankle, a fractured sternum, fractured ribs and three cracked vertebrae.
Giving evidence, Topham told the jury he and his wife had taken two cars because of the amount of presents they had with them, including a bike for his eldest son.
His wife left her parents first in her Volvo XC90, and he reversed off the drive a few minutes later after carrying his two sons to the BMW and defrosting his windows, Topham explained.
Topham said his eldest son, then aged five, was strapped in a car seat behind him, with his youngest son, then aged two, strapped in a car seat behind the front passenger seat with his teddy and blanket on his lap. The family dog was also in the boot.
“As we set off my eldest said my youngest had dropped his teddy,” Topham told the jury.
Topham said he carried on, assuming his youngest son had fallen asleep, but then heard a “piercing scream.”
“Initially he started a small whine as children do and then let out a massive scream and would not stop,” Topham explained.
“For me it was like the sound of a burglar alarm going off.
“When he was younger there were stages where I had to pass him to my wife and walk out the room.”
Topham said he believed his son had grown out of the screaming, which he described as “crazy “
“I honestly don’t believe I thought about what I was about to do.”
Topham agreed there had been previous occasions where he had pulled over and stopped after one of his children had dropped something.
Asked by defence barrister Paul Greaney QC why he didn’t stop on this occasion, Topham replied: “I wish I did, but I didn’t.
“But I honestly believe it was the scream that led me to instantly react and get that teddy.”
Topham told the jury he took his left hand off the steering wheel and began searching in the rear footwell for the teddy while still keeping his eyes on the road.
“Initially I put my hand back, and then turned my head to look at the child.”
When he looked back at the road Topham said he just saw headlights in front of him.
“I don’t recall hitting the car, I just recall waking up to the airbag in my face, and my kids screaming.”
Topham told the jury he checked his children were okay and then opened Mr Regler’s car door.
“I said to Mr Regler ‘is everyone okay?’
“Mr Regler said ‘I’m okay, but my wife isn’t looking very good.”
At that point Topham said he rang 999 for help.
In an account to a police officer just minutes after the collision, Topham said he looked away for a split second.
However, during a later interview, when asked to estimate the time Topham counted to three.
When asked during his evidence to explain the different accounts, Topham said his first recollection to the police officer was clear and honest.
Topham told the jury that since the collision he had sat on his drive in a stationary car and looked round for three seconds.
“Three seconds is a long time, I don’t believe it was that long,” Topham added.
Topham said the family had been stopping at a lodge at Tattershall Lakes over Christmas 2019 and went to a local pub for Christmas dinner.
“I had a small glass of wine, it didn’t have any effect at all.”
After the lodge ran out of gas they decided to visit his wife’s parents at their country home which they had bought with the lottery win.
Topham said he left school at 16 and joined his father’s painting and decorating business.
At the age of 22, Topham told the jury he experienced a life changing experience.
“My wife placed a ticket on the Euromillions, we won £45 million.”
Asked by Mr Greaney if the couple received a life changing amount of money, Topham replied: “Absolutely.”
Topham said the money allowed them to pay off mortgages for his friends and father, and buy a collection of cars.
“We bought Rushmoor Farm which was a dream for Cassie’s parents.”
The couple, who now have a third child aged just four months, also bought a £250,000 home in a ‘normal street’ - but have since moved.
“It (the lottery win) gave us the freedom to give people a step up in life.”
Topham admitted along with the lottery win came a burden of press intrusion.
“We moved three times, we disappeared off the radar. That’s when it felt good to win the lottery. We don’t flaunt our wealth.”
Asked by Mr Greaney, referring to the press intrusion, if he would give it all back Topham replied: “No, I don’t think anyone would.”
The jury heard Topham had been driving for 12 years and had never previously been involved in an accident or got any points on his licence.
Topham told the jury he did attend one speed awareness course after he towed a trailer two miles an hour above the speed limit.
Under cross examination from prosecution barrister Michael Cranmer-Brown, Topham admitted his driving was careless.
Asked to estimate how long he looked away from the road, Topham said he could not be sure, adding, “I think it was a split second.”
Rodney Regler, in a statement read to the jury, said: “It’s simple. The other car was on my side of the road and I had no chance to react to avoid a collision.”
The jury was read details of police interviews in which Topham admitted he was at fault, saying: “I turned round to get the teddy and that was my mistake.”
Topham, of Swinderby, denies causing the death of Mary Regler by dangerous driving on Christmas Day 2019.
The jury has been told that he admits the lesser charge of causing her death by careless driving.
Topham also denies causing serious injury to Rodney Regler by dangerous driving.
The charges follow the head on collision on Louth Road, North Cockerington, near Louth, on December 25, 2019.
The trial continues.